Find the midpoint of a line whose endpoints are (-1, 3) and (4, 9).

Given coordinates: A(-1,3) and B(4,9)

Here, x₁ = - 1, y₁ = 3 and x₂ = 4 , y₂ = 9

let the coordinates of midpoint AB = (x, y)

We know, Co-ordinates the mid-point of $\mathrm{AB}=\left(\frac{{\mathrm{x}}_1+{\mathrm{x}}_2}{2},\frac{{\mathrm{y}}_1+{\mathrm{y}}_2}{2}\right)$

$=\left(\frac{-1+4}{2},\frac{3+9}{2}\right)$

$=\left(\frac{3}{2},\frac{12}{2}\right)$

$=\left(\frac{3}{2},6\right)$

Thus, the coordinates of the midpoint AB(x, y) $=\left(\frac{3}{2},6\right)$